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H. P. GASKILL DUPLEX ENGINE.

No. 370,776. Patented oct. 4, 1887,.

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DUPLEX ENGINE.

No. 370,776. Patented ont. 4,1887.

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H. F. GASKILL.'

DUPLEX ENGINE.

No. 370,776. Ptemd ont. 4, 1887.

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UNITED STATES PATENT Ori-ICEO HARVEY F. GASKILL, OF LOOKPORT, NEW YORK.

DUPLEX ENGINE.l

SPECIFICATION forming part of Letters Patent No. 370,776, dated October4, 1887.

Application tiled April 11, 1887. Serial No. 234,353.

.To all whom it may concern:

Be it known that I, HARvEY'F. GAsKILL, of Lockport, New York, haveinvented certain new and useful Improvements in Duplex Engines, of whichthe following is a specification.

This invention relates to the valve motion of duplex engines. Its objectis to check the motion of the pistons before they reach thecylinder-heads.

To this end the invention consists in giving A each engine of the duplexsystem a control over its own valve during the latter parts of itsstroke, and in certain devices or combinations, all of which arerecitedin the claims at the end hereof.

In the accompanying drawings I have shown so much of the steam end of aduplex engine containing my invention as is desirable for a perfectunderstanding thereof.

This machine consists of two cylinders side by side, their pistons andpiston-rods, their valves and valve-stems, two rock-shafts, connectingdevices between the rock-shafts and the piston-rods by which eachpiston-rod rocks one of the shafts, two arms on each rock-shaft, twolevers pivoted near their middles to the valve-stems, connecting devicesconnecting the ends of the levers to the arms on the rockshafts, andnumerous details of use in making up the finished machine.

In the drawings, Figure l is a top View of the steam end of a duplexpumping-engine, the valve-chests being removed. Fig. 2 is a side view ofthe same. Fig. 3 is an end view of the same, taken from in front. Figs.4 and 5 are modied details.

A and A are the two cylinders; B and B, their respective valves; C andC', their respective valve-stems; E and E', their respectivepiston-rods.

N N N N are' stretchers connecting the steam-cylinders A A with thepumpcylinders, which are not shown, or other parts of the machine.

H is a piece bolted onto the two middle stretchers, and forming bearingsor supports for the rock-shafts.

I and I are the two rock-shafts.

F and F are cross heads or arms, secured to 5o the piston-rods E and E',respectively.

D is an arm on rock-shaft I. G is a link vduring half a stroke.

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connecting said arm with cross-head F on piston-rod E. D is an arm onrock-shaft I. G is a link connecting arm D with the crosshead F onpiston-rod E. By means of these connections rock-shafts I and I arerespectively rocked by piston-rods E and E.

K and K are arms extending upward from the ends of the rock-shaft I.

J and J are levers pivoted near their middles j and j to the valve-stemsGG', and connected at their upper ends to the upper ends of the arms Kand K. The valve-stems are provided with an adjusting mechanism, asshown.

L is an arm extending downward from one end of rock-shaft I. L is asimilar arm, eX- tending upward from the opposite end of thatrock-shaft.

M is a link connecting arm Lwith the lower end of lever J.

M is a link connecting arm L with the lower end of lever J The operationof this apparatus islas follows: Piston-rod E is at the middle of itsstroke and is moving in the direction of the arrow. This moves the upperends of the two arms K and K, and with them the upper ends of levers Jand J, toward the cylinders. At the same time piston-rod E', which is atthe forward limit of its motion, moves back, carrying arm D with it.This moves the lower end of arm L, and with it the lower end of lever J,toward the cylinders. Both ends of lever J are therefore moved towardthe cylinders, and valve B, which is operated by J, is moved back. Theparts are so adjusted that when piston-rod E reaches the end of itstravel valve B is over both ports, but is immediately moved fartherback, and opens the forward port by the continued motion of rod E. Rod Enow starts back, and thereby moves the upper end of lever J forward, thelower end being at the same time moved backward by rod E, so that valveB is substantially stationary Thus it will be seen that valve B Qfengine A is closed bythe action ofthe pistons of both engines, andopened by the action of the piston E of the opposite engine. In asimilar manner valve B is operated. Starting with the position of theengines shown in Fig. 2, the upper end of lever IfO J/ is moved back byrod E, and itslower end, aeted on by arm L', is moved forward by rod E.As the tWo ends of the lever are moving in opposite directions, itscenter is substantially stationary, and valve B', which is connected toits center, is also substantially stationary, and remains so until oneof the pistons changes the direction of its motion. This occurs when Ereaches the, end of its stroke, E being at that time at the middle ofits stroke. From this point until E reaches the end of its stroke thetwo ends of lever J are movedin the same direction-to Wit, forwardandValve B is closed thereby.

By means of the adjusting-screws c c (see Fig. 2) the pistons can bepermitted a certain amount of travel without moving the valves, and thusthe stroke can be variedeither shortened or lengthened.

In Figs. 4 and 5 I have shown modifications of the connections betweenthe two rock-shafts and the levers J J These will be readily understoodby the mechanic, as will also many other modifications which he mayadopt Without departing from my invention.

l. The combination, in a duplex engine, of the valves, the valve-stems,the levers pivoted to the valve-stems, the adjusting-screws for varyingthe throws of the valves, and connecting devices connecting one end ofeach lever with one set of pistons and the other end of eaeh lever withthe other set of pistons, substantially as set forth.

2. The method of regulating the motion of a duplex engine havingindependent pistons Consisting in causing both sets of pistons to actabout equally upon both sets of valves, eausin g the pistons to offseteach other in their actions on the valves during one part of the stroke,and to re-enforce each other in their actions on the valves duringanother part of the stroke, substantially as set forth.

3. The method of regulating the motion of a duplex engine havingindependently-moving pistons, consisting in causing both sets of pistonsto act about equally on both sets of valves, causing said pistons tooffset eaeh other in their actions on the valves during the first partsof the strokes, and to re-enforee each other in their actions on thevalves during the latter parts of the strokes, substantially as setforth.

HARVEY F. GASKILL.

Witnesses:

H. H. FLAGLER, PERRY STOWELL.

